58 REPORT—1850. 
“ consisting of clay,” and the higher grounds reposing on the sides of the hills 
above it ({. 6. the under stratum), as “of a gritty sand.” 
Now the great shocks of Calabria, three in number, were almost vertical, 
and spoutings of water, both out of wells and crevices, and out of spots 
where before there was neither aperture nor water, were numerous. And 
these conditions give me the means of explaining the very curious circum- 
stance of the sand-cones and circular hollows found in the plain of Rosarno, ἡ 
as described by the Calabrian Government Commissioners, and also figured 
and described by Sir C. Lyell (Principles of Geol. p. 465). They say, ‘in 
the plain of Rosarno were found numerous circular hollows, for the most 
part about the size of a coach-wheel, but some larger and some smaller; these, 
like wells, were full of water within a foot or so of the surface; on digging 
down, they were found to be funnel-shaped cavities in the clay, full of sand, 
and some which were dry presented nothing but an inverted cone of sand in 
the clay-bed, concave in the centre on the top, and rippled off at the edges. 
Eye-witnesses had seen these hollows suddenly formed by the spouting up 
of water mixed with sand during the earthquake, which was thrown to a 
considerable height. In the great Chilian earthquake of 1820, M. Place 
describes similar sand-cones as formed on the banks of the river Concon, 
fifteen miles from Valparaiso, each, he says, with a crater-like cone in the 
inside ; and he describes the plain there as clay with a substrate of sand.” 
(Quart. Journ. vol. xvii.) And Mrs. Graham, in her description of the 
Chilian earthquake of 1822-23, says, “In all the small valleys the earth of 
the gardens was rent and quantities of water and sand forced up through 
the cracks to the surface. In the alluvial valley of Vefia a la Mar, the whole 
plain was covered with cones of earth about four feet high, occasioned by 
the water and sand which had been forced up through funnel-shaped hollows 
beneath them, the whole surface being thus reduced to the consistence of a 
quicksand.” (Geol. Trans. vol. i. 2ud ser. p.414.) Similar sand-cones, under 
similar conditions, are recorded in the ‘ Philosophical Magazine,’ vol. ix. 
p- 72, as having been formed during an earthquake at the Cape of Good Hope 
on December 5, 1809. 
Thus this phenomenon is seen not to be an isolated or peculiat one, but 
common to several earthquake-shaken countries resting on water-bearing 
sand beds. Sir W. Hamilton “thinks the phenomenon easily explained ;” 
thus, “the impulse having come from the bottom upwards, the surface of 
the plain suddenly rising, the rivers which are not deep would naturally dis« 
appear, and the plain returning with violence to its former level, the rivers 
must naturally have returned and overflowed, at the same time that the 
sudden depression of the boggy grounds would as naturally force out the 
water that lay hid under their surface.” He says he obsetved that ‘‘ where 
this sort of phenomenon had been exhibited the ground was always low and 
rushy.” His explanation is scarcely intelligible, and certainly not true. I 
am not aware that any other writer has attempted a rigid explanation of the 
spoutings of water and sand, ὅδ. in earthquakes, but from what has preceded, 
I think I may lay claim to having, for the first time, done so; and we may 
now see that the Calabrian sand-cones were simply the ajutages through 
which in the lowest places, and where the swampy clay offered the least resist+ 
ance; the bed of water, reposing in the great sand-formation beneath, broke 
forth at the moments of vertical shock, sweeping up more or less of the sand, 
along’ with the water. 
The form of these cones, as figured in section by Sir Charles Lyell, is pre- 
cisely that which an issuing fluid would shape to itself. Wemay readily see 
now what prodigious secondary effects in dislocation and removal of masses, 
such violent and sudden hydrostatic pressure brought to bear under a large 
